Boot Device Priority on IBM Lenovo ThinkCentre?

I'm running on an IBM Lenovo ThinkCentre and am attempting to boot from the CD ROM drive but I can't seem to find boot disk priority option in startup menu.

Guest

When you turn your computer On, press "Enter" key. It will show you a Menu, from where you can goto BIOS or use a temporary boot device.

Rizwan

You probably need to set the drive, as the boot drive through the BIOS.

Frostfire